The temp here is in the mid-30°s and, as of this afternnoon, the monovalves in Lilly (300D) and Sybill (300SDL) have both crapped-out. Lilly's has been marginal for a while but Syb's was fine until now. The failed mono is a nice compliment to her leaking sunroof too...

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Never a dull moment at Berry Hill Farm.

See, that's your problem with living in Texas.

Ought to move up here where it's a balmy 42F.

Just waitin' for that ice storm to hit...

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

raining like crap here in houston....but whats new. weather.com shows a very intimidating radar for those up north tonight. good luck all. at least its not as bad as kansas/missouri.

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1980 300D

You can't fool me; my son used to live on the other side of Ronkonkoma from you and I KNOW it gets cold there.

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Never a dull moment at Berry Hill Farm.

.........nah......doesn't get cold anymore......dropped below freezing about three times this winter.........couldn't be related to global warming however.......

Sybil could be one of the more appropriately named cars on this forum......
I thought when the monovalve failed you got full time heat. I guess you also get no heat if diaphragm is torn?

The sunroof is not leaking. Sybil is crying. You don't want to upset Sybil......

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I replaced my monovalve last summer when I was bored. The old one had a torn diaphram so I was getting almost no heat, new one is in great condition and works flawlessly. Drove home in the sleety, snowy, icky weather this morning and was coddled in warmth and comfort by my W126. Cranked right up with a 6 second glow at 24F after sitting almost 1.5 days. We're supposed to get hit bad over the next few days....bring it on!

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I think that a torn diaphragm will allow some heat at idle but when there's a lot of flow through the valve (highway speed) it kinda balls-up. But you're right in thinking that an open circuit/no voltage condition fully opens a functional monovalve.

When it dries up some, I'm going to cover the sunroof joint on Sybill with clear packing tape...or Dap™ bathub caulk.

__________________
Never a dull moment at Berry Hill Farm.

Sybill better not be like that when we get there in March...

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

Are the drains on the W126 the same basically as on a W123? Is your problem at the connection point at top of A-pillar?
Good ol' Marlene.........

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I'll trade you my low 0's for your mid 30's.

Better not mention the 70's we had today... Very nice.